Milk pump



NOV. 18, 1952 A, MA ES MILK PUMP Filed Oct. 23, 1948 3 Sheets-Sheet 2 INVENTOR ATTORNEY'S MILK PUMP Filed Oct. 23, 1948 3 Sheets-Sheet 5 INVENTOR Zaslie A. fizz 46s TORNEY Patented Nov. 18, 1952 UNIT D STATES PATIENT oFF1cEf' 2,618,225 MILK PUMP I y Leslie 4. Mapes, Palisade, N. J. Application October 23, 1948,"Se rial No. 56,203

The present invention relates to a novel, and improvedsanitary pump particularly adapted for the pumping'of milk, cream and other liquids.

Objects and advantages of the invention will beset forth in part hereinafter and in part will be obvious herefrom, or may be learned by practic'e'with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims; V

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to herein'and constituting a part hereof, illustrate one embodiment of the invention, and together with the description; serve to explain the principles of the'invention.

Of the drawings:

Figure 1 is a vertical central sectional view of a typical and illustrative embodiment of the present invention, taken on the line l-I' of Figure 2; Figure -2 is a central sectional view taken on the line 2--2 of Figure l and Figure 3 is a cross section taken on the line 33 of Figure 1.

The present invention has for its object the provision of a novel and improved sanitary pump which-can be easily and rapidly taken apart for cleaning and sterilizing. A further object is the provision of an improved pump which produces a steady flow of liquid with substantially no pulsation of the liquid and with very little turbulence such as might cause churning of milk or cream into butter. A further object is the provision of an improved sanitary pump which minimizes the danger of contamination of the pumped liquid and which is subject to little wear in long periods of-operation.

The present invention provides a conveniently accessible pump structure in which the liquid is moved by a pair of rotors, rotating on parallel axes within a single pump chamber which comprises two overlapping generally cylindrical cavities-at one side of which is an inlet, while the outlet is at the other side of the pair of cavities. Therotors are each of a somewhat eccentrical shape, and are mounted to fill the axial space in the cavities between the bottom of the cavities and the cover member by which the cavities are closed. The rotor shafts are driven by means of a centrally disposed worm meshing with worm gears on the shafts so that the rotors are driven in opposite directions at equal speeds and what wear .there is on the gears is equal, the worm 3 Claims. (01. 103 -1122 2 drive at the same time effecting. whatever. speed reduction is needed from the driving motor..

In order to render assembly and .disassembly more convenient and to reduce the possibility of contamination of the liquid by lubricant, the pump chamber is vertically disposed and has its upper end closed by a removable cover. The rotorsare preferably splined to their shafts'and are supported on the shafts so that the bottom of each rotor rests in substantial contact with the bottom of the pump chamber, while the top of the rotors are in substantial contact with the cover plate. By removal of the cover plate, the rotors are exposed for easy removal by axial movement off the shaft ends, and they are preferably located at a convenient height to be lifted by the operator while standing. While in operation, the rotors are held in place by gravity with only a slight running clearance with the cover plate.

Each rotor is formed as a somewhat eccentric member, preferably being truly cylindrical throughout two opposite quadrants, but on different radii, the two cylindrical portions being joined by spiral portions so there is a smooth transition from one cylindrical surface to the other. The rotors are duplicates of each other and are timed so that the large diameter cylindrical portion of one rotor is close to the small diameter cylindrical portion of the other rotor'and after of rotation of both rotors, the situation is reversed for the two rotors.

Positioned between the two rotors and closing the space between them is a resilient member bearing against both rotors for their full axial length which member is movable to accommodate the movement of both rotors, thereby sepa rating the inlet and outlet chambers and preventing leakage of the pump at the overlapping portion of the rotor paths.

The pump chamber is mounted on the driving housing for easy removal over the upper ends of the driving shafts and is sealed thereto by means of packing rings which can be removed with the pump chamber and replaced separately.

It will be understood that the foregoing general description and the following detailed description as well are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to the illustrative and preferred embodiment of the invention as shown in the accompanying drawings, the driving means for the pump comprises a housing [0 having a cover plate l2 secured thereto by cap screws M to is rotatably journalled by anti-friction bearings bearings 21 are mounted in suitable seats formed" in the cover plate 12, the bearings being held on the shaft by means of locking rings 28., As shaft and worm I6 rotate, the shafts 22 and-23-'-are -ro-- tated at a slower speed in opposite-angular clirections and at equal speeds. Shafts 22 and 23 project upwardly from the cover plate [2 and areadapted to extend in-to.'a pump chamber to be supportedoncoverplate l2 Pump-ceasing comprises a: bottom .wallpore tionSl, side wall portion 32, and .azcover. portion 34,.and'ithe; bottom wall portion. 31*is grooved tore'ceivea. locating spacer. biar 36f which also extendsintoa groove 31. formed on .the upper surfaceiofthe cover: i2, serving: to locate. and space. the. bottom wall 3! in. the desired .spatial relation to; the cover. plate l2. Suitable packing 38 is' proVidedJbetWeen the: cover". plate i2.'=and thebott'om plate 3! surrounding each of the shafts 1:22 and 23,,therebyassisting. the shoulders 39.011v shaftsf22 and-23 in preventing oil creeping-upand into thepurnp casingBfi.

Pump casingtfi has-its bottom wall sifornied with two-apertures to receive the shafts. 22 and Hand which .these shafts mayfreelyrotate, thespace between the bottom wall 3| and the shafts 22 and23being sealed by means of the o'rin'gs: 42 of the usual rubber or other resilient material, being seated in suitable annulargrooves surrounding the shafts.

The uppersurface of the bottom wall 3| of the pump chamber. is preferably flatexcept for the O ring grooves. Plate 31 together with the side wall :memb-er 32 is shaped to provide two slightly overlapping" cylindrical cavities 4-6 of substantial axial length which cavities merge into each other and are connected at one side to aninlet 48 and at the other side to an outlet 59; the inlet and outlet being parallel cylindrical holes which have substantially the same axial-extent as the cavities lfi andcommunicate with the cavities 25 throughout their length. Preferably, and as shown, the centers of the inlet 48 and the outlet 50 are equidistant from the centers of the cylindrical cavities 46.

The upper open end of the pump casing 39 is closed by means of the cover plate 34, which is secured to the wall portion 32 by means of wing nuts on screw studs 54, is provided with an inlet pipe 58 and an outlet pipe 58 aligned respectively with the inlet 68 and outlet 56.

Within each of the cylindrical cavities 46 is rotatablymounted a rotor 60, the two rotors coacting to drawliquid into the pump through the inlet id-and expel it underpressure through the outlet 50. Each rotor 60 comprises an eccentric member. ofnan axial length substantially equal to. the distance between the upper face of bot- Each of the rotors 60 is of uniform cross section throughout its length, and the two rotors are preferably duplicates of each other. Each rotor is formed with its surface which may be conveniently described as four separate parts. The surface of the rotor from point A to point B is preferably truly cylindrical and of a radius equal to the radius of the cavity 46, neglecting running clearance. The surface of the rotor 60 from point C/to-"pointi-D. is.:al's'o preferably truly cylindrical'but of a considerably smaller radius than the portion A B. The surfaces of the rotor from B to C and from A to D are both spirals so that a smooth transition occurs from the surface A B to the surface C D at both sides of the rotor. In'other-words there is a constant increase per degreerin the radius of the curve from C to D and a similar constant increase from D to A. Thesurfaces A B, B C, C D, and D A are each and the surfaces ALB and C D are opposite quadrants.

as will be seen-afrom .gan. inspection of Figure-3'; the junctions .ofz-theinletpassagegfi l with the cylindricaL' cavities 1135 are. spaced; 90? fromtthe junctions .58 .of theoutlet 50 with .the cylindrical cavitieslle and. as the rotorsrfiflare rotated,.-the spacein each cavity is is shut oif'from .thez-inlet 481 at the. moment that the. space isopenedto thevouatlet fiil-and remains..closed withrespect to the inlet 58 until the rotor has completed-270% of. rotation. By reason ofthe spiral form of the connecting surfaces :3 C.-and:D A; the right-hand rotor Bil deliversn'o liquidto the outlet 50'until point B has passed theiunction point v 66 after which it' delivers liquid at; an increase-:inrate until point C passes pjointtt at. whichtime-the ratezbecomes constant until point D passes point 56. As point D passes point 65 thera'te-dim-ine ishes and the flow ceases whenpoint' A-arrives at point 56. During this full rotation of the right-hand rotor 60 the left-handzrotor operates at an equal speed but'its action is timed 1805 later than that of the right-hand. rotor. 60 so that it begins to deliver: liquidito the. outlet .50

; just as the right-hand rotor begins 'to' deliver a diminishing quantity of liquid and :the left-hand rotor Bil-begins to deliver a diminishingquantity of liquid'jus-t as therig-h-t-hand rotor-.begins-to deliver anincreasing quantity'of liquid. Thereby substantially'allpulsationinthe deliveryof the liquid'is' eliminated and .aconstant rate-of flow obtained.

In order to seal the inlet 48 from the outlet 50 between the rotors 69; there: is provided a-mov-- able member" positioned between the two-rotors:- This member preferably comprises a block-J0 of soft, yielding; material such as rubber, which is compressed between the rotors 6i); having'its op posite and relatively long sides cylindricallywon. cave and of a: curvature corresponding;approximately to the curvature.ofsrotorsfifl in thequa-da rants C. D. To form a betteri wearingsurface for the resilient andmovableiblock- 79; it is ex'-. ternally sheathed by arelatively thin, flexible pivotal movement between the rotors 60 at'their point of adjacency, and extendsxtofillthespace:

between'the bottom .wall :3! andthe cover;:plate:

34, being heldxin position by means ofavpi'nnor.

abutment 16- which is heldin-the shallow 'slots; 1'! formed: in the cover plate; 34 iandi-bottom wallu 3|, preventing the possibility of block bein forced from between the rotors 60. This block 10 thus effectively separates the chambers 46 into inlet and outlet chambers. A second pair of slots 11 may be provided on the opposite side of the rotors 66 and with the pin 16 in these slots the pump may operate in the reverse direction.

Rotors 60 are drivingly connected to their respective shafts 22 and 23 by th upper splined portion of the shafts and the rotors are shouldered to rest on shoulder 18 and lightly in contact with the bottom wall 3| of the chamber.

In pumping liquid such as milk, cream and the like, it is essential that the pump be thoroughly washed, cleaned and sterilized at least daily. Whenever the operation is necessary, it is easily, quickly and effectively accomplished with the pump of the present invention by removal of the wing nuts on screws 54 which allows the cover plate 34 to be removed. After this the rotors 60 may be lifted from their driving shafts 22 and 23 and thereafter the pump chamber 30 as a whole may be lifted off the upper shaft ends so as to permit sterilization of the complete apparatus so far as it ever comes in contact with the liquid being pumped. Due to the fact that the rotors 60 may be lifted upwardly, and may be replaced by reverse movement, and also due to the fact that the normal height of the rotors is at a convenient level, they may be easily handled by the operators, and the operation of this assembly and re-assembly is much simpler and rapid than has heretofore been the case.

By positioning the pump chamber entirely above the driving mechanism and above any parts requiring lubrication, contamination of the milk or other liquid is rendered almost impossible, and any leakag developing in the 0 rings 42, or between the shafts 22 or 23 and the bottom wall 3|, will allow escape of milk from the pump rather than the escape of lubricant into the pump.

Wear on the gears 24 is equalized as they are always subjected to the same movement and forces, and thus there is no danger of their getting out of time and thus developing leakage.

The invention in its broader aspects i not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. A sanitary pump including in combination a pump body having a vertically disposed chamber therein, a drive shaft extending vertically in said chamber, said chamber having a substantially flat bottom wall and said chamber being vertically movable onto and away from said shaft, sealing means axially movable along the shaft to seal the upper face of the chamber bottom wall to the shaft, a pump rotor splined to the shaft and held by gravity thereon and against the upper face of the chamber bottom wall, a sealing cover overlying and closing said chamber and contacting with the upper face of the rotor, and inlet and outlet means carried by said cover and removable therewith whereby the cover, rotor and chamber may be easily disassembled for cleaning and sterilization.

2. A sanitary pump comprising a pump body having a single vertically disposed pump chamber therein, said chamber comprising two cylindrical cavities of equal diameter in slight overlapping relation and having a substantially flat bottom wall and inlet and outlet ports on opposite sides of the chamber, said cavities communicating with the inlet and outlet ports and being positioned adjacent the intersections of the cylindrical cavities, and two rotors which are eccentric with respect to their respective axes of rotation, one rotatable in either cavity, said eccentric rotors running in substantial contact with the cavity walls, each rotor being formed as a generally cylindrical body, two diametrically opposed quadrant surfaces of each rotor being cylindrical and of different radii, said cylindrical quadrant surfaces being connected by spiral surfaces, drive shafts extending vertically in each of said chambers over which the chamber may be lifted, sealing means axially movable along the shaft to seal the upper face of the chamber bottom wall to the shaft, each shaft being splined to receive its rotor and allo the rotor to rest by gravity on the bottom wall, a sealing cover overlying and closing the chamber and contacting with the upper face of the rotor.

3. A sanitary pump as claimed in claim 2 in which a resilient floating member positioned between the two rotors seals the space between them.

LESLIE A. MAPES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 46,457 Ellis Feb. 21, 1865 785,248 Yokouchi, et a1 Mar. 21, 1905 1,550,099 Sayre Aug. 18, 1925 1,771,863 Schmidt July 29, 1930 1,969,651 Kretschmer Aug. 7, 1934 2,097,881 Hopkins Nov. 2, 1937 2,232,951 Kosian Feb. 25, 1941 2,247,454 Thomson July 1, 1941 2,276,355 VanRanst Mar. 17, 1942 2,293,541 Hall Aug. 18, 1942 2,308,742 Brown, et al Jan. 19, 1943 2,380,283 VanRanst July 10, 1945 2,400,485 Cardillo May 21, 1946 2,451,603 Barker Oct. 19, 1948 2,453,284 Tornborg Nov. 9, 1948 FOREIGN PATENTS Number Country Date 6,328 Great Britain 1904 244,445 Great Britain Apr. 8, 1926 593,620 Great Britain Oct. 21, 1947 594,469 France June 22, 1925 658,011 France Jan. 21, 1929 694,369 France Sept. 15, 1930 777,814 France Dec. 5, 1934 

